Epistemology is the science of knowing. It is an orderly way of thinking and deciding when something has been proven. Epistemology sets a higher standard than “That makes sense,” or “I suppose that could be true.” Epistemology requires three things: truth, justification, and belief. If you believe something, and if you have a good reason to believe it, and if it is indeed true, then it is reasonable to say that you know it. Let’s consider each of those requirements.

Belief

Words alone do not express belief. Children memorize and recite the alphabet, the multiplication tables, poems and passages of scripture. Parrots can be taught to quote Shakespeare. In these cases, the truth is declared, but the speaker doesn’t understand what they are saying so they can’t believe it. They are just making noises. Belief comes when the speaker or thinker understands and believes the meaning of the words.

Justification

Justification means having a a good reason to believe the idea. It means having sufficient assurance that the idea deserves to be believed. It’s the difference between being told the neighbors have a new puppy, and going next door and seeing the puppy for yourself.

There are two kinds of justification: experience and authority.

Authority

Authority is assurance from any source outside yourself. It could be a book. It could be an eyewitness to an event. Authority is our source of information about everything outside our immediate experience. You trust authority for news about recent events in South America, Asia, Europe or Africa. More fundamentally, you trust authority that South America, Asia, Europe or Africa exist at all. Unless you’ve travelled there, Europe is no realer to you than Middle Earth, or Oz, or Gilder and Florin. If your impulse is to say, “But of course Europe and Africa exist,” you are demonstrating a willingness and ability to trust authority.

Authority isn’t always reliable. Experts make mistakes. Sometimes they deceive you on purpose. Before you accept justification from an authority you have to determine if the authority is reliable. Knowing which experts to trust is probably the most important exercise in epistemology for modern Americans. (See my related articles about expert error regarding George W. Bush, Kitty Genovese, and Lew Wallace.)

An expert source can be trusted if it has been correct often in the past about similar matters, and if the subject being discussed is knowable. If someone assured you they know the way to Applebee’s or how to choose a ripe watermelon, you can believe them. Those things are simple and knowable. But if someone says they can predict a winning lottery number or next year’s Super Bowl winner, you shouldn’t believe them. Not even if they won the lottery in the past; nor even if they are a professional sportswriter. Future outcomes are unknowable and predictions are usually foolish.

Experience

Experience is the justification your get from seeing or hearing and encountering something up close. You don’t have to suffer a toothache, or childbirth, or appendicitis to know they are painful. Watching someone else with empathy and compassion is enough for you to share the experience. Still, you can’t be 100% sure of things — even when you see them with your own eyes. The agony you observe on the face of a sufferer might be faked.

Have you been to Niagara Falls or the Grand Canyon? Then you have true belief in their existence with the justification that you saw them with your own eyes. I’ve traveled in Europe, Africa, the Caribbean and Asia, and my experience justifies my belief that those are real places. I’ve never been to South America, but my daughter lived in Paraguay and I accept its existence on her authority. Another daughter assures me that Japan and Australia are real. No one I know has ever been to the South Pole or to the moon, but I believe in them on the authority of books and films.

Epistemological Problems

A man stands at the edge of a lake in Minnesota one misty morning and sees what appear to be two ducks floating on the water. He knows what a duck looks like, and his eyes tell him that what he sees are ducks. He concludes there are ducks on the lake this morning. But he is mistaken about what he sees. They are not ducks, but wooden decoys left by a hunter. The man sees no real evidence of ducks. Meanwhile, further away in the mist there are ducks he can’t see.

This man believes a true fact, justified by belief in false evidence.

A man reads a news story about a dog attack, in which a boxer mauls a child to death. He wonders if boxers are the most vicious and dangerous breed of dog. Being conscientious, he looks online and finds a report saying more serious dog bites come from Labrador retrievers than any other breed. He concludes that Labs, not Boxers are the most dangerous dog. His facts are right, but he still comes to the wrong conclusion because he doesn’t justify his conclusion.

The frequency of bites linked to dog breeds is proportionate to the number of dogs. Labrador Retrievers bite the most only because they are the most popular breed of dog. Pit bulls (whether they are purebred American Staffordshire Terriers or mixed-breed) are the exception. Pit Bulls are around 3% of all dogs in America. But they account for the majority of fatal dog bites year after year. Pit Bulls are by far the most vicious and dangerous breed of dog.

This man believes a false conclusion, justified by belief in true evidence.

A 23-year-old Texas man named Cameron Todd Willingham was executed in 2004 for the arson murder of his three little girls. At his trial, experts testified they found evidence in the charred remains of the house proving that the fire had been started on purpose with lighter fluid.

Several witnesses, including a police chaplain, testified at the trial that Willingham stood calmly and watched the house burn from a safe distance while his children died inside. Those same witnesses had told reporters on the day of the fire that Willingham was distraught and desperate to save his children. In fact, Willingham’s hair and clothes were scorched by flames from his efforts to get back into the house, and police eventually restrained him with handcuffs to keep him out of firefighters’ way. Those details were written down in police reports but not mentioned during the trial.

When people tell a story, they choose details that suit the narrative. Psychologists say people actually remember differently depending on circumstances at the moment they are remembering. During the preliminary investigation, those witnesses were standing on the sidewalk experiencing tragedy. But weeks later they were testifying in a courtroom. The formality of the courtroom implied Willingham’s guilt. The actions they had seen with their own eyes on the day of the fire didn’t fit with that setting. So they were omitted.

The expert testimony in Willingham’s case was probably wrong, too. The arson investigators made mistakes while sifting through Willingham’s burned-out bungalow.

The whole field of arson investigation as it existed in the 1990s was based on assumptions that had never been tested. Much of what the experts thought they knew about fire was wrong. The experts testified in Willingham’s trial that the “intense heat” of the fire proved that some extra fuel had been used. But when researchers got around to comparing fires under different conditions they found that once something as big as a house gets burning, it burns exactly as hot whether it was initially stoked with fuel or not. (More details about the shoddiness of expert witness is found in this excellent New Yorker article and also this John Oliver report.) Willingham was probably innocent of the murder charge.

The jury in Willingham’s case believed false information based on false authority.

Going Further with Epistemology

There is much more to epistemology than is discussed here. There is a role for skepticism. The old Motown lyric, “Believe half of what you see, and none of what you hear,” is a pretty good heuristic, but in this day of the “deep fake,” you can’t trust what you see, either.

You can learn more by reading any good book on the subject. But what you can learn by studying logic and epistemology is limited. It is far more important to ponder whether you can trust your sources.